#pragma GCC optimize(2, "Ofast", "inline")
#include <iostream>
#include <vector>
#include <map>
#include <cmath>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>
#include <algorithm>
#define endl '\n'
#define int long long
#define pii pair<int, int>
using namespace std;

// 已知
int n, k, x;
string a[11];
// 未知
vector<string> ans;

void dfs(string now, int cnt)
{
    if (cnt == k)
    {
        ans.push_back(now);
        return;
    }
    for (int i = 0;i < n;++i)
    {
        dfs(now + a[i], cnt + 1);
    }
}

signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    cin >> n >> k >> x;
    for (int i = 0;i < n;++i) cin >> a[i];
    dfs("", 0);
    sort(ans.begin(), ans.end());
    cout << ans[x - 1];


    return 0;
}